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The db840DVC 8" subwoofer boasts a rigid polypropylene cone and durable Santoprene™ surround built to handle big power over the long haul. The dual 4-ohm voice coils allow you to wire your system to draw maximum power from your mono amp or to safely hook up multiple subs. Match a db sub to a suitable enclosure, and enjoy impressive low-frequency performance rarely found in this price range. And Polk certifies this sub for marine applications, so they're a great choice for your boat too.

Note: If you are wiring this DVC sub for lower impedance, make sure that your amp is compatible. Most car amplifiers are stable down to 2 ohms in standard mode, or 4 ohms in bridged operation.

To drive this subwoofer, we recommend a mono subwoofer amplifier that can put out between 135 and 270 watts RMS at 2 ohms. For more information please refer to our article on How to Match Subwoofers and Amplifiers.

What's a component sub and why would I want one?

A component sub is simply a speaker that's designed to reproduce bass once it's installed in a compatible enclosure. Think about the impact of a movie soundtrack in a big theater or even in your own home HDTV setup. A component sub can add the same kind of power to the music in your car. And a car sub is not all about the boom that you hear on a street corner (although that's cool too) - you can pair a component sub with your choice of enclosure to get bass just the way you like it, from tight and punchy to fat and loose. And once you experience music in your car with a well-tuned subwoofer, you'll never go back.

Product Research

Features

Dual 4-ohm Voice Coils: This woofer features dual 4-ohm voice coils
that offer wiring flexibility. When the voice coils are wired in parallel
the woofer presents a 2-ohm load, when wired in series the woofer presents an 8-ohm load.

Polypropylene Cone: The cone is made with polypropylene, which
provides durability while being lightweight and rigid. The cone is supported by
a vented cone/coil coupler, which stiffens the cone for greater mechanical
stability and lower distortion.

Santoprene
Surround: The Santoprene surround is resistant to extremes in temperature,
humidity, and exposure to sunlight for excellent long term reliability.

Triple-vented Kapton Voice Coil
Former: Triple venting of the 4-layer Kapton Voice Coil Former, Cone/Coil
Coupler and Pole Piece contribute to the high power handling and reliability of
the db Series subs.

Break-In Period: Polk db subwoofers will achieve even greater
performance once they are thoroughly broken-in. To break in a new db Sub, play
music through it for 20 to 30 hours at moderate levels.

Enclosure Compatibility

Recommended Sealed Box Volume: Polk recommends
mounting this woofer in a sealed enclosure made out of 3/4" MDF with an internal
volume of 0.35 cu/ft.

Recommended Ported Box Volume: Polk recommends a ported enclosure made out of 3/4" MDF with an
internal volume of 0.60 cu/ft using a 3" diameter x 11" long port.

Recommended Bandpass Box Volume: Polk recommends a bandpass enclosure
made of 3/4" MDF with a total internal volume of 0.90 cu/ft. The bandpass box
should have a 0.40 cu/ft sealed rear chamber and a 0.50 cu/ft ported front
chamber with a 4" diameter x 12" long port.

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team. They verify what’s in the box, check the owner's manual, and record
dimensions, features and specs. We stay on top of new products and technologies
to help people make informed choices.

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Polk db840

Written By Drew, Hawaii on Friday, March 13, 2015

"Coolness Factor"

Build Quality

Ease of Use

Sound Quality

Value

Have the svc version in a sound ordanance .38 sealed box. Feeding it 300 watts rms and it takes it like a champ. Rattles the car more than I expected.

Great value for the money

Installed this last year for my son in his 2001 GMC Yukon XL. Like others, it fits but with minor modification to mounting rim. I took the cardboard mounting rim off the old subwoofer and used it as a spacer for this one; used tape to seal out air leaks. Sounded OK but that was with factory amp. This year's xmas present was a new Kenwood X598 stereo (see separate review). Huge difference. Don't hesitate to change out all the factory speakers and factory garbage stereo; you will be amazed!

8" Sub for 03 Expedition

I've had this installed in my 03 expedition for a week now and I have no complaints. I used an aftermarket amp attached to it and it sounds amazing. Definitely an improvement from the stock set up. It doesn't rattle the expedition, but it definitely gives it a nice deep low sound that the door speakers wouldn't be able to produce themselves. I did have to use heat gun to help push out the back the plastic stock subwoofer enclosure and drill my own holes, but besides that the setup was relatively easy.

Nice Subwoofer Speaker!

We bought it to replace the 8" speaker in our Advent 8" Powered Subwoofer for our home theatre and it works great! Because of the dual voice 4 ohm coils, we were able to wire the subwoofer in series to the 8 ohms we needed for the Advent unit. It fit into our unit like it was made for it! I couldn't believe it when the screw holes lined up! I'm planing to buy another one and install it in my car. Shallow depth makes it great in a little car.

Great Speaker

This is a great speaker with excellent versatility. The dual voice coil makes it easy to connect in stereo at 4 ohms or mono at 2 ohms. The sound quality is great. The only problem I ran into was the rubber gasket around the out side of the speaker is slightly wider than the speaker itself, and had to be trimmed to fit in the factory sub enclosure in my Tahoe. The space tolerance is very tight in the box.

Pleasantly surprised.

Purchased this sub and some small enclosures for my 2000 Chevy pickup. With the limited space under and behind the rear seats I decided to use an 8" sub, I wasn't expecting much. After wiring and test fitting the enclosures I was pleased at how little room I lost, but still thought with the smaller size my bass wouldn't be very powerful. However after powering up the first time and only using half or so volume I was blown away! I don't expect to win any competitions with only 100 watts but I'm very pleased with my system. I'm planning on buying another to fill the other enclosure and can't wait to see how that sounds. Crutchfield has once again helped me find exactly what I was looking for and at a great value! Due to my budget for this project I was expecting to have to settle for okay bass instead I have amazing bass, and I can say I've got a Polk sub.

These 8" subwoofers produce bass like high end 12" subs.

With slight modifications this speaker fit in my factory sub location and it sounds great. I have a five channel Alpine V12 with a Kenwood head unit, and i don't have to turn up the volume to get a head to toe massage. When i crank the music, it sounds like I have 2 12"s that are competition quality. My Suburban sound like an Imax Theater when i play video games or movies and my family loves it. I didn't even lose any grocery/ seating/ or storage space, you can't even tell that I have a pounding system unless you know about it (my poor neighbors).

Pros:Awesome punch for the price, clear as heck, and a great price.

Cons:I only had to make minor modifications to put this in my factory suburban enclosure. Otherwise nothing bad to say, at all.

Great price on a great sub

I replaced the stock sub in my Yukon and only had to do 2 quick mods to get it to work. I installed it in under 45 minutes and couldn't be happier with the improved sound and clarity. I would recommend this for anyone looking for a quality sub for a great price.

Pros:Inexpensive, great sound, built well

Cons:Couldn't use Polk supplied gasket to seal speaker to factory box. I had to use a strip of foam tape.

Polk Audio db840DVC

Installed the Polk Audio db840DVC in my 2001 Chevy Tahoe. Had to modify slightly to drop down to 2 ohms, which was easy to do. Fit easily into the existing box in the rear cargo area of the vehicle. Excellent sound!

Pros:Easy to install and excellent sound.

Cons:Had to wire the voice coils in parallel in order to drop down to 2 ohms.

Didnt Fit - Polk Audio db840DVC

I would have loved to use this Sub - but this was the first time that something they told me would fit didnt. I have a 2001 Suburban with a factory Sub in the rear and it requires a shallow mount Sub. This Sub was 4" deep. I had it wired and ready to install - because they recommendations had always worked before. This is 1 case where I guess their information for the Suburban isnt always correct. I was disappointed because the price etc was just what I wanted.

Pros:Nice Sub - I've liked Polk in the past - rating is based on if I could have used it

Great replacement sub for stock 2001 Tahoe/Yukon

Have a 2001 Chevy Tahoe that had an old, dry rotted, 8" subwoofer as part of the non-Bose system. This model Polk sub was a recommendation by Crutchfield's customer service. Wow! Very pleasantly surprised. The stock GM amp does well with this sub wired down to 2 ohms. I had to omit the rubber surround ring to get the sub to fit in the factory box. A few holes quickly drilled and the job was complete in short order....maybe 45 minutes, tops.

Pros:Great sound, excellent value.

Cons:Can't use rubber surround ring in my application....but that's the only downside I see.

Awesome

I needed some base in my boat, I have used Polk Audio before and find their sound quality to be second to none.I am not disappointed in this one either. I put one sub in a .5 cubic foot box connected to an older 250 watt, with alow pass filter, bridgeable Jensen amp that I had laying around. It sounds awesome. Super tight and rich. The only thing disappointing is Crutchfields specs on the MM series. They look the same but on Polk Audio's site the MM's are much more efficient. I would have sprung for the MM's had I discovered this before purchase. But this sub is still AWESOME!!!

Finally some Bass!

Just installed the Polk db840DVC in my 2001 BMW Z3 Roadster and, WOW, what a difference! I finally have some Bass I can actually feel and hear. My goal was to have more bass without losing trunk space or leg room in the cabin. I replaced the stock 5.25" subwoofer and had to do some custom modifications to make this 8" driver fit in the factory location but, it turned out great! I have replaced the stock head unit with a JVC Arsenal HD receiver that has many variable settings for the bass response and I have found that using the 60hz bass boost setting really makes this driver hit hard. I am still using the stock power amps so, I think it will sound even better once I replace them. That will be the next upgrade. This Polk gives great bass at a fantastic value. I bought mine from the scratch and dent sale but it looks brand new! I had read many reviews about the lack of bass in the Z3 due to it being a convertible but after getting the Polk and with a little work, I have BASS!!!

Totaly Surprised !!!

Written By Robert, Sarasota FL on Friday, May 18, 2012

"Coolness Factor"

Build Quality

Ease of Use

Sound Quality

Value

I have been building custom car audio systems for 20 yrs now. I got into car audio when I was 14 and at 34 I am still hooked. I bought an 07 Silverado shortbed reg cab and space is extemely minimal. I built 2 wedges for behind the seat with a sealed down fire design and HOLY MOLY. I can not believe the sound of these little woofers. One of my neighbors came over to check out the awesome sound coming from my truck and said "Wow how did you fit 12s back there ? Are those low profile subs ? " When I showed him he was blown away. I am blown away !!! I kid you not in the right box these subs are un beatable in sound quality. Crystal clear punch and low end bass notes with out a hick up. I am Running a Kenwood DDX616 6.1 touch screen and a Kenwood KAC-7202 for power to these Polks.

And just as a reference to my ear for sound I run a single Infinity Kappa Perfect M3D 12 in my CTS that knocks things of shelves in my nieghbors apartments !

Awesome speaker

I bought this sub to replace the blown original in my Advent powered
subwoofer in my home theater. the spec's were comparable and I hoped it
would workout ok. The sound out of this little 8" is amazing. The bass is far
deeper, crisper and tighter than it ever was with the original. The best part is
that it doesn't overpower the rest of the system while watching a movie. It fit in
perfectly with my old Polk speakers and new Denon AVR 1911 receiver. Money
well spent.

Replacement Woofer for A Logitech Z-680 System

Needed an 8 inch, 8 ohm subwoofer to replace in my Logitech system. This one fit perfectly.
No cutting or drilling necessary. Just be sure to remove the rubber gasket. Doesn't have as
much boom as the original woofer but that is okay because the original one overpowered
the rest of the system anyway. This one gives the system a nice balance now. Great
product. Should sound nice in the car if you like your bass nice and tight and not boomy.

BOOM... boom

I redid my 98 Expedition in all Polk speakers and included this sub. Overall for the price, I think that it is a great bargain. It's got good sound to it, volume is decent, but it you are looking for large amounts of bass, I don't think that this is the best sub. If you are wanting something that is great to use to watch movies and goes well with most types of music while not too over powering, I don't think that you can go wrong with this mid-range sub.

Polk Audio db840DVC

Outstanding value. I put together a mid-level system for an older mini-truck with an RF 450 Punch for the solitary amp. I am running this speaker bridged on the rear out put of the RF amp and could not imagine needing any more belt from a sub-woofer. Great buy, excellent support.